<template>
  <div ref="dragDiv" class="drag">
    <div class="drag_bg" />
    <div class="drag_text">{{ confirmWords }}</div>
    <div ref="moveDiv" :class="{'handler_ok_bg':confirmSuccess}" class="handler handler_bg" style="position: absolute;top: 0px;left: 0px;" @mousedown="mouseDownFn($event)">
      <i class="el-icon-d-arrow-right" style="font-weight: bold" />
    </div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      beginClientX: 0, /* 距离屏幕左端距离*/
      mouseMoveState: false, /* 触发拖动状态  判断*/
      maxWidth: '', /* 拖动最大宽度，依据滑块宽度算出来的*/
      confirmWords: '请向右拖动滑块进行验证', /* 滑块文字*/
      confirmSuccess: false /* 验证成功判断*/
    }
  },
  mounted() {
    this.maxWidth = this.$refs.dragDiv.clientWidth - this.$refs.moveDiv.clientWidth
    document.getElementsByTagName('html')[0].addEventListener('mousemove', this.mouseMoveFn)
    document.getElementsByTagName('html')[0].addEventListener('mouseup', this.moseUpFn)
  },
  methods: {
    // mousedown 事件
    mouseDownFn: function(e) {
      if (!this.confirmSuccess) {
        e.preventDefault && e.preventDefault() // 阻止文字选中等 浏览器默认事件
        this.mouseMoveState = true
        this.beginClientX = e.clientX
      }
    },
    // 验证成功函数
    successFunction() {
      this.confirmSuccess = true
      this.confirmWords = '验证通过'
      this.$emit('confirmSuccess') // 验证成功后执行登录事件
      if (window.addEventListener) {
        document.getElementsByTagName('html')[0].removeEventListener('mousemove', this.mouseMoveFn)
        document.getElementsByTagName('html')[0].removeEventListener('mouseup', this.moseUpFn)
      } else {
        document.getElementsByTagName('html')[0].removeEventListener('mouseup', () => {})
      }
      document.getElementsByClassName('drag_text')[0].style.color = '#fff'
      document.getElementsByClassName('handler')[0].style.left = this.maxWidth + 'px'
      document.getElementsByClassName('drag_bg')[0].style.width = this.maxWidth + 'px'

      document.getElementsByClassName('el-icon-d-arrow-right')[0].style.opacity = '0' // 验证成功后右箭头设置为透明
    },
    // mousemove事件
    mouseMoveFn(e) {
      if (this.mouseMoveState) {
        const width = e.clientX - this.beginClientX
        if (width > 0 && width <= this.maxWidth) {
          document.getElementsByClassName('handler')[0].style.left = width + 'px'
          document.getElementsByClassName('drag_bg')[0].style.width = width + 'px'
          this.confirmWords = '请向右拖动滑块进行验证'
          document.getElementsByClassName('drag_text')[0].style.color = '#fff'
        } else if (width > this.maxWidth) {
          this.successFunction()
        }
      }
    },
    // mouseup事件
    moseUpFn(e) {
      this.mouseMoveState = false
      var width = e.clientX - this.beginClientX
      if (width < this.maxWidth) {
        document.getElementsByClassName('handler')[0].style.left = 0 + 'px'
        document.getElementsByClassName('drag_bg')[0].style.width = 0 + 'px'
        this.confirmWords = '请向右拖动滑块进行验证'
        document.getElementsByClassName('drag_text')[0].style.color = '#000'
      }
    }
  }
}
</script>
<style scoped>
    .drag{
        position: relative;
        background-color: #e8e8e8;
        width: 100%;
        height: 40px;
        line-height: 40px;
        text-align: center;
        border: 1px solid #ccc;
        border-radius: 4px;
        margin-bottom: 20px;
    }
    .handler{
        width: 40px;
        height: 38px;
        border: 1px solid #ccc;
        border-radius: 4px;
        cursor: move;
        color: #145fda;
        background: #fff;
    }
    .handler_bg{
        color: #145fda;
        font-weight: bold;
        /* background: #fff url("") no-repeat center; */
    }
    .handler_ok_bg{
        border-top-left-radius: 0;
        border-bottom-left-radius: 0;
        background: #fff url("") no-repeat center;
    }
    .drag_bg{
        background-color: rgb(20,95,218);
        height: 38px;
        width: 0px;
        border-radius: 4px 0 0 4px;
        color: #fff;
    }
    .drag_text{
        position: absolute;
        top: 0px;
        /* color: #145fda; */
        width: 100%;text-align: center;
        -moz-user-select: none;
        -webkit-user-select: none;
        user-select: none;
        -o-user-select:none;
        -ms-user-select:none;
    }
</style>
